It wouldn’t be an Australian Open without at least few days of searingly hot weather.
But how hot is too hot?
With extreme UV warnings and temperatures forecast to hit 40°C in Melbourne on Saturday and 41°C next Tuesday, AllSportsPeople explains how tournament organisers decide when playing conditions need to be adjusted—or even suspended—to ensure the welfare of players, fans, ball kids and officials.
What is the Australian Open Extreme Heat Policy in 2026?
The AO Extreme Heat Policy is based on a five-level Heat Stress Scale (HSS) that is used to assess if conditions are safe and whether matches should continue, with a rating of 5.0 representing the most extreme playing conditions and a likely suspension of play.
MORE: Australian Open LIVE, Scores, schedule, results, updates for AO tennis 2026
The HSS is based on four climate factors—radiant heat, air temperature in the shade, relative humidity and wind speed—measured at different locations around the Melbourne Park precinct.
In 2026, the ATP has also introduced new heat rules (the WTA already had them) that stipulate cooling breaks be offered to players when conditions exceed the allowable threshold of 30.1°C.
The threshold isn’t the air temperature, but rather a metric known as the Wet-Bulb Globe Temperature (WBGT) and, once activated, either player can request a 10-minute break after the second set to hydrate, change clothing, shower or use other cooling methods such as fans and ice vests under the supervision of AO medical staff.
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What is the Wet Bulb Globe Temperature?
Extreme heat regulations in many professional sporting codes, including tennis, now rely on the Wet-Bulb Globe Temperature.
Unlike a simple temperature reading, the WBGT provides a far more accurate measure of the overall impact of heat on athletes (and fans) by taking into account a range of additional markers including the level of humidity.
This is important because the higher the humidity, the harder it is for the human body to release heat through the evaporation of sweat.
When does play get suspended?
Under the Australian Open’s Extreme Heat Policy, the Tournament Referee is ultimately responsible for determining whether cooling breaks or suspensions of play are necessary.
The HSS and WBGT measurements are continually monitored around Melbourne Park and if the HHS reaches 5.0, the Tournament Referee will suspend the start of new matches on outside courts.
If matches are already underway they will continue, but only until they reach a natural break such as the end of an even number of games, or at the completion of a tie-break.
On show courts with roofs such as Rod Laver Arena and Margaret Court Arena play will also be suspended when the next natural break is reached.
However on these courts the Tournament Referee has the option to have the roof closed for the remainder of the match, as well as any following matches while the Extreme Heat Policy remains in effect for outside courts.